#!/bin/bash
# ============================================================================
# Gitea Restore Script
# ============================================================================
# Restores PostgreSQL database, Gitea data, and configuration from S3 backups
#
# Usage: ./restore.sh <timestamp>
#   Example: ./restore.sh 20260611_140530
#
# This will restore backups with the specified timestamp from S3
# ============================================================================

set -e

# ============================================================================
# Configuration
# ============================================================================
readonly S3_BUCKET="qvest-task-backups"
readonly S3_PREFIX="backups"
readonly RESTORE_DIR="/tmp/gitea-restore"
readonly LOG_FILE="/var/log/gitea-restore.log"

readonly DB_CONTAINER="gitea-postgres"
readonly DB_USER="gitea"
readonly DB_NAME="gitea"
readonly DATA_VOLUME="gitea_gitea-data"
readonly CONFIG_DIR="/opt/gitea"

# Output colors
readonly GREEN='\033[0;32m'
readonly YELLOW='\033[1;33m'
readonly RED='\033[0;31m'
readonly NC='\033[0m'

# ============================================================================
# Logging Functions
# ============================================================================
log_info() {
    echo -e "${YELLOW}[INFO]${NC} $1" | tee -a "${LOG_FILE}"
}

log_success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1" | tee -a "${LOG_FILE}"
}

log_error() {
    echo -e "${RED}[ERROR]${NC} $1" | tee -a "${LOG_FILE}" >&2
}

error_exit() {
    log_error "$1"
    cleanup
    exit 1
}

# ============================================================================
# Validation Functions
# ============================================================================
validate_timestamp() {
    if [[ ! "$1" =~ ^[0-9]{8}_[0-9]{6}$ ]]; then
        error_exit "Invalid timestamp format. Expected: YYYYMMDD_HHMMSS"
    fi
}

check_s3_backup_exists() {
    local timestamp="$1"
    local file="$2"
    
    if ! aws s3 ls "s3://${S3_BUCKET}/${S3_PREFIX}/${file}-${timestamp}.tar.gz" &>/dev/null && \
       ! aws s3 ls "s3://${S3_BUCKET}/${S3_PREFIX}/${file}-${timestamp}.sql.gz" &>/dev/null; then
        return 1
    fi
    return 0
}

# ============================================================================
# Core Functions
# ============================================================================
cleanup() {
    if [ -d "${RESTORE_DIR}" ]; then
        rm -rf "${RESTORE_DIR}"
    fi
}

create_restore_dir() {
    mkdir -p "${RESTORE_DIR}" || error_exit "Failed to create restore directory"
}

download_backups() {
    local timestamp="$1"
    
    log_info "Downloading backups from S3..."
    
    aws s3 cp "s3://${S3_BUCKET}/${S3_PREFIX}/database-${timestamp}.sql.gz" \
        "${RESTORE_DIR}/" || error_exit "Failed to download database backup"
    
    aws s3 cp "s3://${S3_BUCKET}/${S3_PREFIX}/gitea-data-${timestamp}.tar.gz" \
        "${RESTORE_DIR}/" || error_exit "Failed to download Gitea data backup"
    
    aws s3 cp "s3://${S3_BUCKET}/${S3_PREFIX}/config-${timestamp}.tar.gz" \
        "${RESTORE_DIR}/" || error_exit "Failed to download configuration backup"
    
    log_success "Backups downloaded successfully"
}

stop_services() {
    log_info "Stopping Gitea services..."
    
    cd "${CONFIG_DIR}" || error_exit "Failed to change to config directory"
    docker compose stop gitea || error_exit "Failed to stop Gitea"
    
    log_success "Services stopped"
}

restore_database() {
    local timestamp="$1"
    
    log_info "Restoring database..."
    
    # Drop and recreate database
    docker exec "${DB_CONTAINER}" psql -U "${DB_USER}" -d postgres \
        -c "DROP DATABASE IF EXISTS ${DB_NAME};" || error_exit "Failed to drop database"
    
    docker exec "${DB_CONTAINER}" psql -U "${DB_USER}" -d postgres \
        -c "CREATE DATABASE ${DB_NAME};" || error_exit "Failed to create database"
    
    # Restore from backup
    gunzip -c "${RESTORE_DIR}/database-${timestamp}.sql.gz" | \
        docker exec -i "${DB_CONTAINER}" psql -U "${DB_USER}" -d "${DB_NAME}" \
        || error_exit "Failed to restore database"
    
    log_success "Database restored"
}

restore_gitea_data() {
    local timestamp="$1"
    
    log_info "Restoring Gitea data..."
    
    # Clear existing data
    docker run --rm \
        -v "${DATA_VOLUME}:/data" \
        alpine sh -c "rm -rf /data/*" \
        || error_exit "Failed to clear Gitea data"
    
    # Restore from backup
    docker run --rm \
        -v "${DATA_VOLUME}:/data" \
        -v "${RESTORE_DIR}:/backup:ro" \
        alpine tar xzf "/backup/gitea-data-${timestamp}.tar.gz" -C /data \
        || error_exit "Failed to restore Gitea data"
    
    log_success "Gitea data restored"
}

restore_configuration() {
    local timestamp="$1"
    
    log_info "Restoring configuration files..."
    
    # Extract configuration backup
    tar xzf "${RESTORE_DIR}/config-${timestamp}.tar.gz" -C "${CONFIG_DIR}" \
        || error_exit "Failed to restore configuration"
    
    log_success "Configuration restored"
}

start_services() {
    log_info "Starting Gitea services..."
    
    cd "${CONFIG_DIR}" || error_exit "Failed to change to config directory"
    docker compose up -d || error_exit "Failed to start services"
    
    log_info "Waiting for services to be ready..."
    sleep 10
    
    log_success "Services started"
}

verify_restore() {
    log_info "Verifying restore..."
    
    # Check if Gitea is responding
    if curl -f -s http://localhost:3000 > /dev/null; then
        log_success "Gitea is responding"
    else
        log_error "Gitea is not responding - manual verification required"
    fi
    
    # Check database connection
    if docker exec "${DB_CONTAINER}" psql -U "${DB_USER}" -d "${DB_NAME}" \
        -c "SELECT 1 FROM public.user LIMIT 1;" &>/dev/null; then
        log_success "Database is accessible"
    else
        log_error "Database verification failed"
    fi
}

# ============================================================================
# Main Execution
# ============================================================================
main() {
    if [ $# -ne 1 ]; then
        echo "Usage: $0 <timestamp>"
        echo "  Example: $0 20260611_140530"
        echo ""
        echo "Available backups:"
        aws s3 ls "s3://${S3_BUCKET}/${S3_PREFIX}/" | grep "database-" | \
            sed 's/.*database-\([0-9_]*\)\.sql\.gz/  \1/' | sort -u
        exit 1
    fi
    
    local timestamp="$1"
    
    log_info "Starting restore process for timestamp: ${timestamp}"
    
    validate_timestamp "${timestamp}"
    
    if ! check_s3_backup_exists "${timestamp}" "database"; then
        error_exit "Backup with timestamp ${timestamp} not found in S3"
    fi
    
    # Confirm restore
    echo ""
    log_error "WARNING: This will replace all current data!"
    read -p "Are you sure you want to continue? (yes/no): " confirm
    if [ "$confirm" != "yes" ]; then
        echo "Restore cancelled"
        exit 0
    fi
    
    create_restore_dir
    download_backups "${timestamp}"
    stop_services
    restore_database "${timestamp}"
    restore_gitea_data "${timestamp}"
    restore_configuration "${timestamp}"
    start_services
    verify_restore
    cleanup
    
    log_success "Restore completed successfully"
    echo ""
    log_info "Please verify the system is functioning correctly:"
    log_info "  1. Access https://git.poll-streams.com"
    log_info "  2. Login with your credentials"
    log_info "  3. Verify repositories are accessible"
    log_info "  4. Check system settings"
}

main "$@"